Standard accounts of concepts in philosophy and in cognitive psychology hold that we learn a target concept by learning the concepts that constitute it. If this is the only model of learning we have, then only concepts that are complex or structured can be learned. Orlandi argues for an alternative to this framework by presenting a proposal for how we learn some atomic concepts. Orlandi shows that we can learn a concept through descriptions without thinking that the concepts employed in the descriptions constitute the target concept. Orlandi develops this idea by employing a general externalist explanatory strategy and by using the notion of a mental file. In the view Orlandi develops, some concepts are akin to files in that the descriptions associated with a given concept are means of properly individuating the extension of the concept, and they are also means of connecting a concept to others, but they do not constitute the concept and can be revised or abandoned. Orlandi then gestures at the repercussions of this view for the field of conceptual engineering.